The present invention relates to an apparatus for reading images such as photographs, pictures and symbols, and more particularly, to an image scanning apparatus that can use light penetrating an original or reflected light from an original to read originals of differing size and that are the object of read.
In general, the originals that are scanned by image scanning apparatus are large in size, such as drawings that are printed on paper, and there are various sizes down to small sizes such as 16-millimeter film. When image information printed on paper such as memorandum and document paper or the like is scanned, the image that is to be scanned is irradiated with light and the light that is reflected from the image is collected and read performed. In addition, when an image that is written on a material such as photographic film which is light-transmissive, the light is made to pass through the original which is to be read, and the transmitted light is collected to perform read.
In this manner, image reading apparatus that perform read of an image by using the reflected light that is reflected by, or the light that is transmitted through the original are known as having a reflecting mirror that sends the light that is irradiated from a light source and transmitted through the original or the light that is reflected from the original, an image forming lens and an image sensor to which the light that passes the image forming lens is irradiated.
In general, there are many cases where large-sized originals have their images read by using reflected light and there are many cases where originals for which the penetrating light is used to read the image are small in size. Because of this, an original platen on which an original having its image read by using reflected light is placed, is generally provided on an upper surface of the body casing of the main unit of the image scanning apparatus. In addition, an original platen on which an original having its image to be read by using transmitted light is usually internally incorporated into the body casing of the main unit. In an image scanning apparatus having such a structure, there must be a light source in order to generate reflected light or a light source to generate the penetrating light. In addition, the optical system to irradiate the reflected light onto the image sensor and an optical system to irradiate the penetrating light onto the image sensor must also be provided. Because of this, the structure of the apparatus not only becomes complex but the size of the entire apparatus also becomes large. Moreover, it is also necessary to have a powerful light source when the penetrating light is to be used to read an image, and this necessitates a large light source and also causes the problem of dissipating the heat generated. Furthermore, when an image is to be read by changing the magnification ratio, it is necessary to move the reflecting mirror that is disposed in the optical system. When this is done, it is necessary to consider the interference of the two optical systems when the reflecting mirror is moved.
Accordingly, in an apparatus that reads images using the light that is either transmitted through an original or reflected by it, and object of the present invention is to provide an image scanning apparatus which has a simplified structure and is compact overall.
In addition, another object of the present invention is to provide an image scanning apparatus that has a compact light source and a small amount of generated heat.
Still another object of the present invention is to provide an image scanning apparatus that has no interference between the two optical systems.